HxH: I Will Be Supreme

Oboro had surpassed the timeline of the original work, becoming the new Demon King before Tanjiro could. The irony wasn't lost on him—the person destined to save the world had instead claimed its darkest throne.

As he flexed his transformed fingers and felt the surge of demonic power coursing through his veins, a wry smile crossed his features.

"This kind of flesh-and-blood power..." he murmured, testing the limits of his new form.

From a purely physical standpoint, his body far exceeded those of most other life forms in the Hunter x Hunter world. The cellular regeneration alone was remarkable—as long as a single cell survived, he could reconstruct his entire being in moments. His enhanced strength, speed, and durability placed him leagues beyond any ordinary human.

Yet, it was pitifully weak by the standards he knew.

In terms of raw destructive potential, this demonic flesh wouldn't survive a single strike from Netero's Hundred-Type Guanyin. Zeno's aura alone could vaporize every cell in his body without leaving ash. This doesn't even consider the various Nen abilities that could bypass physical reality entirely, such as manipulation types that could control him like a puppet or emission techniques that attack the soul directly.

The crucial difference, of course, is that the Hunter x Hunter world possesses Nen as its fundamental power system. The Demon Slayer world had no equivalent energy source.

But within this realm, his new body had reached the absolute pinnacle. The enhancements were significant yet reasonable; he hadn't become impossibly overpowered, just definitively superior. The greatest improvement wasn't raw strength, but rather the ability to walk freely under the sunlight—the one weakness that had defined and limited every demon before him.

His current state reminded him of Kars from JoJo's Bizarre Adventure—the ultimate life form who achieved perfect immortality only to be launched into space, where he became a conscious yet helpless statue for eternity. Even the most powerful beings could be neutralized by the right circumstances.

The recovery abilities he'd inherited from Muzan had been amplified beyond their original scope. While the future demon king, Tanjiro, would have gained only immunity to sunlight and resistance to Nichirin blades, Oboro's transformation included cellular-level regeneration bordering on true immortality.

As for Doma and Kokushibo, he had freed them from Muzan's control but hadn't imposed his own will upon them. The contradictions between the two Upper Moons and their former master could never be resolved through words alone.

A battle was inevitable. They would settle their grievances with bloodshed.

"It's almost finished," Oboro said softly, turning his face toward the rising sun that no longer threatened to burn him alive. "There's nothing more I need to do. Now, I simply wait for everything to blossom and bear fruit."

With his enhanced perception, he could sense the will of the world itself. What had begun as a withered sapling was now a strong, healthy tree with vibrant green leaves that provided abundant shade. The metaphorical greenhouse protecting this reality had reached its structural limits.

The next step would be the final one: the production of fruit. This represented the absolute extent of his capabilities in this dimension.

He had helped the "little tree" grow as tall as the space-time barriers would allow. If it grew any higher, it would shatter the "roof" above—the dimensional walls that kept this world stable and separate from others. He lacked the power to transcend such fundamental limits.

The greenhouse that he perceived as protecting this realm represented the upper boundary of what the Demon Slayer world could become. Even with his intervention and complete renovation of the future power systems, it would still rank among the lowest in the higher world classification hierarchy.

Comparing it to the Hunter x Hunter world was laughable.

Among higher worlds, Hunter x Hunter stood near the apex of complexity and danger. This wasn't just because of Nen abilities or the human world's potential; it was because of the Dark Continent's existence.

Based on his experiences there and his observation of this world's fundamental will, Oboro suspected that the Hunter x Hunter reality had already reached the level of top-tier dimensions.

What defines a top-tier dimension? The most representative example is Dragon Ball, a universe in which entire planets, civilizations, and even galaxies can be obliterated with a casual snap of the fingers. Some characters in that universe could destroy a world like Hunter x Hunter with a single technique.

However, Hunter x Hunter's true strength lies in its incomprehensibly complex power system. There were entities and phenomena that couldn't be killed by conventional force, no matter how overwhelming. Perhaps pure energy wasn't their greatest weakness after all.

This was especially true when dealing with abstract rules and concepts.

However, energy and rules were always relative forces. When rule-based powers clashed with unbearably high energy levels, the rules simply failed to function.

While Hunter x Hunter couldn't match Dragon Ball's raw destructive potential, it possessed a different kind of terrible strength. It was a higher world that had nearly reached top-tier status, standing on the very edge of that classification without quite crossing the line.

Before the shogunate's collapse, Oboro had made careful preparations and accumulated substantial wealth. Though he remained removed from political power, he could still live comfortably in the secular world.

Instead of returning to Yukaku, he changed his appearance and settled in the town beneath Mount Kumotori after some time. The community had grown remarkably prosperous—its borders had expanded, its population had grown, and new architectural styles had emerged that differed significantly from the rigid Edo-period aesthetic.

The world's chaos had finally ended. Unlike the turbulent final years of the Edo period, a strange equilibrium had developed. Though demons still roamed freely, they had formed an unspoken understanding with human society. Combined with the democratic atmosphere of the Dakiji era, it truly felt like a new age had dawned.

Oboro purchased a modest house in the town center. His previous residence had long since crumbled into ruins, claimed by time and weather. He hired a small staff of servants and began living the quiet life of a retired gentleman.

The following day, he made the familiar journey to Mount Kumotori alone.

The Kamado family residence.

Everything felt achingly familiar yet subtly different. The house still stood in its original location in the forest clearing. It had obviously been renovated and expanded over the generations. The basic structure remained unchanged, but new rooms had been added, and the materials looked fresher and more durable.

When Oboro arrived, he found a man splitting firewood and building a cooking fire. A woman hung laundry nearby, humming softly to herself. The domestic scene radiated warmth and contentment.

The man wore the distinctive Hanafuda earrings that had been passed down through the Kamado lineage. His hair and eyes were the same dark crimson that marked every generation of the family. He was clearly a contemporary descendant of the bloodline that Oboro had helped preserve.

"Hello there," the man called out before Oboro could announce his presence. "May I help you with something?"

His five senses were remarkably sharp—he had detected the visitor long before anyone else would have noticed. This awareness stemmed from generations of Sun Breathing training ingrained in the family's daily life.

Since it was summer, it wasn't the season for selling charcoal. According to what Kamado Tanjuro had explained decades ago, this time of year was better suited for gathering wild vegetables or chopping firewood to sell in the markets below.

The man wiped sweat from his brow and approached with a genuinely warm smile. He clearly assumed that Oboro had simply gotten lost in the mountain paths.

But when he took in Oboro's distinctive appearance and clothing, his eyes widened with shock.

"What's your name?" Oboro asked with a gentle smile.

"That black haori..." the man whispered, his voice barely audible. "You...how is this possible?"

The recognition was immediate and unmistakable. He owned an identical outer coat that had been passed down through generations of his family as a treasured heirloom. More importantly, he knew the origin of the garment, which was made from unusual materials.

It had been given to the Kamado family by a man named Oboro over a century ago. His ancestors had even preserved the legendary figure's appearance in the form of detailed wood carvings that still decorated their home.

"I...my name is Kamado Tanjiro," the man said, his throat working nervously.

Oboro could see the familiar features of both Kamado Tanjuro and the future Demon Slayer Tanjiro in this man's face. However, this version was healthier and more robust, without the thin, sickly appearance that had marked his ancestors' struggle for survival. A practical linen kerchief was wrapped around his short-cropped hair.

"You are..." Tanjiro began hesitantly, clearly wanting to voice the impossible question forming in his mind.

Just as Oboro prepared to answer, the man's pupils contracted sharply. His entire posture shifted as he stared at Oboro with sudden, intense focus. In one fluid motion, he raised the hatchet in his hand and pointed it directly at his visitor.

"You are not that great man!" Tanjiro declared with absolute conviction. "You are...a demon!"

"Oh?" Oboro laughed with genuine surprise and delight. "You actually noticed. It seems I was right to help the Kamado family perfect their Sun Breathing techniques all those years ago."